An acoustic device, such as an electro-dynamic inertial vibration exciter, applies bending wave energy to a trim panel to cause the trim panel to resonate and produce an acoustic output. Conventional electro-dynamic inertial vibration exciters, or exciters, are comprised of a magnet assembly rigidly fixed to a housing to define an annular gap, and a voice coil and coil former assembly disposed in the annular gap and rigidly fixed to the trim panel.